21200320 has 56 divisors (see below), whose sum is σ = 51078384. Its totient is φ = 8380416.

The previous prime is 21200303. The next prime is 21200329. The reversal of 21200320 is 2300212.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21200297 and 21200306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30699 + ... + 31381.

It is an arithmetic number, because the mean of its divisors is an integer number (912114).

Almost surely, 2^21200320 is an apocalyptic number.

21200320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21200320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25539192).

21200320 is an abundant number, since it is smaller than the sum of its proper divisors (29878064).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21200320 is an equidigital number, since it uses as much as digits as its factorization.

21200320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 797 (or 787 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 10.

The square root of 21200320 is about 4604.3805229368. The cubic root of 21200320 is about 276.7668932527.

Adding to 21200320 its reverse (2300212), we get a palindrome (23500532).

The spelling of 21200320 in words is "twenty-one million, two hundred thousand, three hundred twenty".